Many known chemical products such as surfactants, plasticizers, solvents, and polymers are currently manufactured from non-renewable, expensive, petroleum-derived or natural gas-derived feedstock compounds. High raw material costs and uncertainty of future supplies requires the discovery and development of surfactants, plasticizers, solvents, and polymers that can be made from inexpensive renewable biomass-derived feedstocks and by simple chemical methods. Using renewable resources as feedstocks for chemical processes will reduce the demand on non-renewable fossil fuels currently used in the chemical industry and reduce the overall production of carbon dioxide, the most notable greenhouse gas.
It is desirable to provide commonly used materials, such as surfactants, plasticizers, solvents, and polymers, from renewable feedstocks as a source of chemical building blocks. It is desirable to provide chemical building blocks that are chemically and thermally stable. It is desirable to provide chemical building blocks having multiple functionalities for subsequent reactions. It is desirable to provide such materials by simple and reproducible methods that can be carried out with ease.
A potential source of materials that are useful as chemical building blocks are cyclic ketals and acetals of oxocarboxylates with polyols. It is known, for example, that polyhydric alcohols, or polyols, having 1,2 and 1,3 hydroxy conformations can react with a ketone or aldehyde to form a cyclic ketal or an acetal (Carey, F. A. and Sundberg, R. J., “Advanced Organic Chemistry Part B: Reactions and Synthesis” 2nd ed., © 1983, Plenum Press, NY, N.Y., p. 544). The 1,2 and 1,3 configurations of hydroxyl groups on a hydrocarbon chain are shown below as (a) and (b), respectively.
Diols such as 1,2-ethane diol (ethylene glycol) and 1,3 propanediol (propylene glycol) are examples of such polyols. Diols having a 1,2 hydroxyl group configuration will form dioxolanes when reacted with ketone or aldehyde moieties, while 1,3 diols will form dioxanes.
Various ketals arising from the reaction of oxocarboxylic acids and esters thereof with diols and triols are known. Ono et al., J. Am. Oil Chem. Soc. 70(1), 29 (1993) disclose ketalization of ethyl pyruvate, ethyl acetoacetate, and ethyl levulinate with various 1-O-alkyl glycerols (diols). Okohara et al., JP 04217972, similarly disclose ketalization of ethyl levulinate with 1-O-alkyl glycerols, followed by saponification of the ester moiety. McCullough et al., U.S. Pat. No. 5,998,092 disclose the ketalization of two keto acids with ethylene glycol. Chirila, Revistade Chimie 28(8), 730-3 (1977) discloses the 1:1 adduct of acetoacetate esters with glycerol. Gelas, Carbohydrate Research 30(1), 21-34 (1973) and Rakhmankulov et al., SU 722912 disclose the 1:1 adduct of pyruvate esters with glycerol and subsequent bicyclic lactone formation.
Ketals of glycerol and levulinic acid or an ester thereof are described in U.S. patent application Ser. No. 11/915,549, the entirety of which is incorporated herein by reference. The ketal reaction product of glycerol with a levulinate results in the ketal acid or ketal ester shown below,
wherein R is hydrogen or an alkyl group. The use of levulinate compounds and glycerol based compounds is particularly useful as both of these starting materials arise from renewable feedstocks. Further, the ketal reaction products are useful for synthesis of a wide variety of surfactants, plasticizers, polymers, and the like.
Efficient synthetic routes to form various compounds based on the ketals or acetals of keto acids, semialdehydes, and the esters thereof are described in U.S. Patent Application No. 61/048,339, the entirety of which is incorporated herein by reference. The synthetic routes described in this applications is useful as a basis for efficient reaction of a number of oxocarboxylic acids and esters thereof with alcohols.
It is desirable to provide new starting materials and synthetic routes to form new varieties of chemical building blocks for monomers, plasticizers, surfactants, and polymers. It is desirable to provide chemical building blocks that arise solely from renewable feedstocks. It is desirable to facilitate synthesis of chemical building blocks that is simple, inexpensive, and scalable for commercialization purposes.